1. Field of the Invention
The present invention relates to a mirror actuator for pivotally moving a mirror about two pivot axes, and a beam irradiation device loaded with the mirror actuator.
2. Disclosure of Related Art
In recent years, a laser radar system has been loaded in a family automobile or a like vehicle to enhance security in driving. Further, the laser radar system has also been used as security measures such as detecting intrusion into a building. Generally, the laser radar system is so configured as to scan a target area with laser light to detect presence or absence of an obstacle at each of scanning positions, based on presence or absence of reflected light at each of the scanning positions. The laser radar system is also configured to detect a distance to the obstacle at each of the scanning positions, based on a required time from an irradiation timing of laser light to a light receiving timing of reflected light at each of the scanning positions.
As an actuator for scanning a target area with laser light, for instance, there may be used a mirror actuator employing a moving coil system configured in such a manner that a mirror is pivotally moved about two pivot axes. In the case where such a mirror actuator is used, laser light is entered into a mirror in an oblique direction. In this arrangement, if the mirror is pivotally moved about two pivot axes in a horizontal direction and in a vertical direction, laser light swings in the horizontal direction and in the vertical direction within the target area.
In the mirror actuator configured as described above, since a driving coil is disposed in a movable portion, it is necessary to supply a current to the driving coil via a cable, a harness or a like member. In this case, however, the cable, the harness or the like member may be flexed as the movable portion pivotally moves, and unstable load may be exerted on the movable portion, which may lower the precision in pivotally moving the mirror.